The impact of significant loss of renal mass resultant from kidney cancer surgery is not fully known. Large clinical studies demonstrate that loss of kidney function correlates with an increased incidence of hospitalizations, cardiovascular events, and all-cause mortality. Patients with renal cell carcinoma (RCC) tend to be older, often have co-morbid conditions associated with lower baseline kidney function, and may be particularly sensitive to further loss of kidney function following kidney cancer surgery. Hence, there is a great need to determine the comparative effectiveness of alternative surgical approaches for RCC on kidney function and downstream clinical outcomes. The goal of this award period is for Dr. Leppert to achieve complete independence as an investigator in urologic health services research and expertise in RCC clinical outcomes. He will receive extensive training through the Clinical Research Track in the Graduate Program in Epidemiology at Stanford University, and through the specific aims of the project. The broad objective of this study is to determine the effect of kidney cancer surgery on kidney function and outcomes associated with chronic kidney disease (CKD) such as end-stage renal disease (ESRD), cardiovascular events, hospitalizations, and mortality. The specific aims of the project are to 1) establish an electronic data registry of persons that underwent kidney cancer surgery within the Veterans Affairs (VA) health care system, 2) characterize the change of kidney function due to specific types of kidney cancer surgery, and 3) to correlate the type of kidney cancer surgery received and post-operative kidney function with the risk of ESRD, conditions associated with CKD, cardiovascular events, hospitalizations, and all-cause mortality among RCC patients in the VA health care system. Ultimately, comparing these surgical strategies can provide opportunities to improve care for patients diagnosed with RCC.